Excel not producing dynamic array output

[James6M]

I teach students using basic Excel.  For the LINEST() function, I have switched over to using the dynamic array style: enter in one cell, no CSE, let the results spill.

I have a student using the exact same version as myself (16.53 (21091200) on macOS), but when he enters LINEST in this fashion, he only gets a single number.  No spilling happens.  He is not using Cntrl-Shft-Enter (I watched).  Why would this be happening?

[#2]

I know when they release updates even if you have the same version you may not have the same features enabled based on you subscription and their roll out. But dynamic arrays has now been released long enough I would not expect that to be the problem. That said, the easiest thing to check is if the students version recognizes DA formulas like FILTER() and UNIQUE(). Also what if they just enter a simple formula with spill over like =B1:B3 , does it spill over then?
If that all works then if you save your file and give that file to them to open will it work?
I hope some of these steps can narrow down the potential cause.

[#3 · Accepted solution]

@mtarlerThanks much for your troubleshooting help.  It turns out that Excel had automatically added a "@" to the beginning of the formula.  I'm not 100% sure what caused that.  But of course removing it returned the expected results.